Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The molecular cloning and characterization of receptors for the nonapeptide hormone family vasopressin-oxytocin was rapidly followed by the identification of mutations in the V2 receptor gene segregating with the clinical phenotype in more than a hundred families with X-linked nephrogenic diabetes insipidus. Together with the recent cloning of the vasopressin-regulated water channel in the apical membrane of the collecting duct tubule and of the identification of rare autosomal recessive nephrogenic diabetes insipidus patients with mutations in the AQP2 gene, these developments enable carrier detection and early diagnosis of infants with congenital nephrogenic diabetes insipidus.
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PMID:Vasopressin receptors in health and disease. 874 82

This review summarizes recent progress in water-transporting mechanisms across cell membranes. Modern biophysical concepts of water transport and new measurement strategies are evaluated. A family of water-transporting proteins (water channels, aquaporins) has been identified, consisting of small hydrophobic proteins expressed widely in epithelial and nonepithelial tissues. The functional properties, genetics, and cellular distributions of these proteins are summarized. The majority of molecular-level information about water-transporting mechanisms comes from studies on CHIP28, a 28-kDa glycoprotein that forms tetramers in membranes; each monomer contains six putative helical domains surrounding a central aqueous pathway and functions independently as a water-selective channel. Only mutations in the vasopressin-sensitive water channel have been shown to cause human disease (non-X-linked congenital nephrogenic diabetes insipidus); the physiological significance of other water channels remains unproven. One mercurial-insensitive water channel has been identified, which has the unique feature of multiple overlapping transcriptional units. Systems for expression of water channel proteins are described, including Xenopus oocytes, mammalian and insect cells, and bacteria. Further work should be directed at elucidation of the role of water channels in normal physiology and disease, molecular analysis of regulatory mechanisms, and water channel structure determination at atomic resolution.
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PMID:Water transport across mammalian cell membranes. 877 26

In a normal adult subject, 12 liters of tubular urine with an osmolality of 100 mmol/kg exit per 24 hours from the loop of Henle. The antidiuretic hormone arginine-vasopressin increases the water permeability of the renal collecting ducts and induces the reabsorption of 11 liters of water: the final urinary osmolality is 1200 mmol/kg for a urinary flow rate of 1 litre per 24 hours. In nephrogenic diabetes insipidus the urine cannot be concentrated maximally. Congenital nephrogenic diabetes insipidus is secondary to either mutations in the AVPR2 gene (Xq28) that codes for the vasopressin antidiuretic (V2) receptor or to mutations in the AQP2 gene (12q13) that codes for the vasopressin dependent water channel. AVPR2 mutations are numerous and diverse: 72 different putative disease causing mutations in the AVPR2 gene have been reported in 102 unrelated families with X-linked nephrogenic diabetes insipidus. AQP2 mutations are rare. Nephrogenic diabetes insipidus could also be secondary to lithium or demeclocycline administration and to hypokaliemia. Some of these conditions are inducing, experimentally, a downregulation of aquaporin II. We encourage physicians who follow families with hereditary nephrogenic diabetes insipidus to recommend molecular genetic analysis because early diagnosis and treatment of infants can avert the physical and mental retardation associated with episodes of dehydration.
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PMID:[Pathological aspects of water transport in the collecting ducts]. 901 68

COS7 cells were transiently transfected with plasmids encoding mutant forms of the V2 vasopressin receptors corresponding to mutations [Y280C, L292P, R337stop, V277A, and G12E (the latter found in the same kindred with L292P)] recently identified in subjects with X-linked nephrogenic diabetes insipidus (NDI). cAMP response to dDAVP and AVP, saturation binding experiments with [3H]-AVP, immunofluorescence, and indirect ELISA studies were performed to characterize the functional consequences of these mutations. The Y280C, L292P, and R337stop mutant V2 receptors show substantially decreased cell surface expression and are functionally inactive. The V277A mutant receptor, though well expressed at the cell surface as seen by immunofluorescence and ELISA and having a dissociation constant with AVP similar to the wild type receptor, was functionally less active as seen by a substantially decreased receptor number (Bmax) and reduced cAMP stimulation by dDAVP. The G12E mutant was functionally the same as the wild type V2 receptor in both cAMP stimulation and binding. These results provide insight into residues critical for V2 receptor expression and function and also provide direct evidence that Y280C, L292P, R337stop and V277A mutations are the cause of X-linked NDI in affected subjects.
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PMID:Functional characterization of five V2 vasopressin receptor gene mutations. 902 23

Most cases of congenital nephrogenic diabetes insipidus (NDI) are inherited in an X-linked manner, which is due to the mutations of the vasopressin type 2 receptor (V2R) gene. However, recent reports have presented female NDI patients with heterozygote V2R gene mutations. The mechanism of inheritance was thought to be skewed X-inactivation. We present a family with congenital NDI. Three male members were diagnosed with NDI, and examination of their V2R gene revealed a G inserted at nucleotide 804 of the open reading frame. Three female individuals display different degrees of symptoms of NDI, and all of them possess both the normal and abnormal genes. The X-inactivation patterns of the female members were investigated via the detection of methylated trinucleotide repeat in the human androgen receptor gene. The grandmother showed extremely skewed methylation of one X chromosome, and the mother revealed moderately skewed methylation. The daughter of the grandmother's sister, who has no symptoms of NDI, showed random methylation. The highly skewed X-inactivation pattern of the grandmother suggests that her NDI phenotype is caused by dominant methylation of the normal allele of V2R gene.
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PMID:Detection of skewed X-inactivation in two female carriers of vasopressin type 2 receptor gene mutation. 932 82

In the last decade, two types of genes participating in the etiology of hypertension have been identified. The primary genes or blood pressure regulators are those that codify enzymes (renin, kallikrein, kininase, aminopeptidase), hormones (angiotensins, vasopressin, aldosterone, prostaglandins, and atrial natriuretic peptide) and substrates (angiotensinogen and kininogen). They cause arteriolar vasodilation or vasoconstriction or sodium retention in the extravascular space. Allelic polymorphisms associated to essential hypertension have been described. The secondary genes are those that produce hereditary diseases of low prevalence, associated to hypertension in 20 to 80% of patients (polycystic kidney disease, pheochromocytoma, adrenal hyperplasia, hereditary nephritis). Forty genes located in all chromosomes, that are dominantly, recessively or X-linked transmitted, have thus far been identified. Chromosomal maps with all genic loci are presented.
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PMID:[The genes of human hypertension]. 946 Feb 75

Nephrogenic diabetes insipidus is a rare, mostly X-linked recessive disorder characterised by renal tubular resistance to the antidiuretic effect of arginine vasopressin. The gene responsible for the X-linked nephrogenic diabetes insipidus, the G-protein-coupled vasopressin V2-receptor, has been localised on the Xq28 region. In this study four patients were investigated with molecular genetic methods. Diagnosis was based on clinical symptoms and lack of increase of urinary osmolality after administration of the arginine vasopressin, or the synthetic vasopressin analogue DDAVP. Three different mutations (C112R, N317K, W323S) were found in three patients, while no mutation was detected in the fourth patient. Since earlier histiocytosis X has been diagnosed in this patient, this patient has probably central diabetes insipidus. Although the main symptoms of the disease can be found in all patients, there are significant differences in the seriousness of the symptoms as well as in some other symptoms. The explanations might be the different mutations in the V2-receptor gene and the various other genetic and environmental factors; these findings provide further evidence that X-linked nephrogen diabetes insipidus results from defects in the V2-receptor gene.
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PMID:[Molecular biological studies on patients with nephrogenic diabetes insipidus]. 957 1

Nephrogenic diabetes insipidus (NDI) is characterized by resistance of the kidney to the action of arginine-vasopressin (AVP); it may be due to genetic or acquired causes. Recent advances in molecular genetics have allowed the identification of the genes involved in congenital NDI. While inactivating mutations of the vasopressin V2 receptor are responsible for X-linked NDI, autosomal recessive NDI is caused by inactivating mutations of the vasopressin-regulated water channel aquaporin-2 (AQP-2). About 70 different mutations of the V2 receptor have been reported, most of them missense mutations. The functionally characterized mutants show a loss of function due to defects in their synthesis, processing, intracellular transport, AVP binding, or interaction with the G protein/adenylyl cyclase system. Thirteen different mutations of the AQP-2 gene have been reported. Functional studies of three AQP-2 mutations reveal impaired cellular routing as the main defect. The great number of different mutations with various functional defects hinders the development of a specific therapy. Gene therapy may, however, eventually become applicable to the congenital forms of NDI. At present all gene-therapeutic approaches lack safety and efficiency, which is of particular relevance in a disease that is treatable by an adequate water intake. The progress with regard to the molecular basis of antidiuresis contributes to the understanding of acquired forms of NDI on a molecular level. Recent data show that lithium dramatically reduces the expression of AQP-2. Likewise, hypokalemia reduces the expression of this water channel. The exact mechanisms leading to this reduced expression of AQP-2 remain to be determined.
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PMID:The molecular basis of nephrogenic diabetes insipidus. 958 67

Loss-of-function mutations in the V2 vasopressin receptor (AVPR2) gene have been identified as a molecular basis for X-linked nephrogenic diabetes insipidus (NDI). Herein, we describe a novel deletion mutation at nucleotide position 102 (delG102) found in a Russian family resulting in a frameshift and a truncated receptor protein. Furthermore, we analyzed the AVPR2 gene of two other unrelated boys with NDI from our patient clientele. These patients showed previously described mutations (R137H, R181C). In-depth characterization of the three mutant AVPR2s by a combination of functional and immunological techniques permitted further insight into molecular mechanisms leading to receptor dysfunction. Premature truncation of the AVPR2 (delG102) led to a drastically reduced receptor protein expression in transfected COS-7 cells and, as expected, precluded specific AVPR2 functions. As indicated by different ELISA and binding studies, the R137H mutant was almost completely retained in the cell interior. In contrast to previous studies, the few mutant receptors in the plasma membrane displayed a low (2.3-fold above basal) but significant ability to stimulate the Gs/adenylyl cyclase system. In contrast to the latter mutation, the R181C mutant is properly delivered to the cell surface but the mutation interferes with high affinity vasopressin binding. Impaired ligand binding is reflected in an about 100-fold shift of the concentration-response curve toward higher vasopressin concentrations with only slightly reduced agonist potency.
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PMID:V2 vasopressin receptor dysfunction in nephrogenic diabetes insipidus caused by different molecular mechanisms. 971 77

Several aquaporin-type water channels are expressed in mammalian kidney and lung: AQP1 in lung microvessels and kidney proximal tubule, thin descending limb of Henle, and vasa recta; AQP2 in apical membrane of collecting duct epithelium; AQP3 and AQP4 in basolateral membranes of airway and collecting duct epithelium; and AQP5 in alveolar epithelium. Novel quantitative fluorescence methods demonstrated very high water permeabilities of the alveolar epithelial and endothelial barriers, and moderately high water permeability across distal airways. In the kidney, water permeability is high in proximal tubule and thin descending limb of Henle, and regulated by vasopressin in collecting duct. The author's laboratory has studied the role of aquaporins in organ physiology using transgenic knockout mice lacking specific aquaporins. AQP1 null mice are mildly growth-retarded, manifest a severe urinary concentrating defect, and have reduced water permeability between airspace and capillary compartments. AQP4 null mice appear normal grossly except for a mild defect in maximum urinary concentrating ability. AQP2-deficient humans have hereditary non-X-linked nephrogenic diabetes insipidus (NDI). In transfected mammalian cells, many NDI-causing AQP2 mutants are retained in the endoplasmic reticulum. The author's laboratory has found that "chemical chaperones," that is, small compounds that promote protein folding in vitro, are able to correct defective AQP2 trafficking in cell culture models. The transgenic mouse and mammalian cell models are thus beginning to provide clues about the role of aquaporins in normal physiology and disease.
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PMID:Role of aquaporin water channels in kidney and lung. 982 13


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